Teenager jailed for retired nurse's savage murder

A teenager who murdered a retired nurse at her home at Callington in the Adelaide Hills has been sentenced to at least 15 years in jail.

Pirjo Kemppainen, 63, was found dead in her home in September 2010.

The South Australian Supreme Court heard the boy was 14 when he stabbed and beat the woman, whom he had targeted at random.

Justice Margaret Nyland said the boy, who pleaded guilty to murder, attacked Ms Kemppainen purely out of his wish to kill someone.

"A particularly disturbing aspect of this crime is that the selection of your victim was entirely random. She was a complete stranger to you and your sole motive to go to the house that night was your wish to kill someone," she said.

She said the attack was savage and required a significant jail term.

"You smashed the sliding door at the back of her house with a concrete brick. You then subjected Ms Kemppainen to what can only be described as a frenzied and relentless attack, initially with a knife and then with a brick," she said.

You then subjected Ms Kemppainen to what can only be described as a frenzied and relentless attack, initially with a knife and then with a brick

Justice Margaret Nyland

"She had multiple stab wounds to her neck, face and head and fractures to her skull."

Justice Nyland raised concern about the boy's prospects for rehabilitation.

She said there was a need to protect the community from further violence.

"In my opinion the premeditated, senseless and savage nature of this crime places it in the very highest end of seriousness," Justice Nyland said.

"I have a received a number of psychological reports to assist me to come to some understanding of what might have prompted you to commit such an horrific crime."

Justice Nyland said psychologist Luke Broomhall and forensic psychiatrist Craig Raeside both had assessed the boy, now 15, and agreed he suffered from a conduct disorder.

'Fixated'

Justice Nyland said four factors were identified by the mental health experts as contributors to the murder.

The boy's low level of cognitive functioning put him in the range of mild mental retardation. The court heard this made it difficult for him to perform academically and impaired his ability to socialise. It made him unable to evaluate the consequences of his actions and what he wanted to do.

His exposure to domestic violence at an early age lead to aggressive and disobedient behaviours.

He was subjected to bullying at school and was ostracised by his peers, which contributed to him becoming somewhat of a social outcast. He developed significant anger and hatred toward people and low empathy for others.

The boy's continued exposure to violent video games and movies decreased his emotional empathy. The boy's recollection of his offending was described as a distant perspective, similar to that of an observer. The psychologist said the boy's lack of empathy toward his victim and lack of revulsion about the blood at the scene were because he had become desensitised by blood and gore he experienced in violent video games and movies.

She said the boy's mental health issues meant he was unable to reason once he had decided to kill.

"Once you became fixated with the idea of killing your victim that was the only idea you were able to contemplate," Justice Nyland said.

She said the teenager had manifested hatred toward Ms Kemppainen despite her being an innocent person who had never harmed him.

"She never had anything to do with you at all," she said.

"The killing of Ms Kemppainen was callous and a cold means to an end. It was all about you regaining power."

The teenager was given a non-parole term of 15 years, initially to be served in a youth detention facility until he is 18.

"It is clear you require many years of treatment to protect the community from any further violence from you," Justice Nyland said.

The teenager automatically received a life prison sentence and Justice Nyland said had it not been for his guilty plea she would have imposed a 25-year non-parole period instead.

The boy has been in custody since his arrest in September 2010 and will become eligible for release when he is 29.

He stood in the dock with his head bowed during the proceedings and was led away without glancing at the judge or members of Ms Kemppainen's family, who were at the sentencing.

The court had been told Ms Kemppainen migrated from Finland in 1968, had enjoyed a quiet life at Callington and was liked by many of the locals.

Justice Nyland said the victim's family knew her as a caring and shy person who had never harmed anyone.

Ms Kemppainen loved gardening and painting and was described in court as a gentle lady who was small in stature but big in spirit.